PURPOSE: To provide a folding seat for a vehicle which is capable of regulating only a sight line of a seated person without separating a main frame.

CONSTITUTION: A movable frame 43 which is rotatable in a forward/back direction to a seat back to a main frame 41 is supported on the main frame 41 through a support member 42, and a regulation mechanism 5 is operated to rotate the movable frame 43 about the center of the support member 42 to the main frame 41, thereby only a sight line of a seated person can be regulated.